A conventional compressor used for an air conditioner and a cooling device generally includes a compression mechanism and an electric motor for driving the compression mechanism, and the compression mechanism and the motor are accommodated in a casing. In the compressor, refrigerant gas which returned from the refrigeration cycle is compressed by the compression mechanism, and the refrigerant gas is sent to a refrigeration cycle. When the refrigerant gas is compressed, a gas compression force is applied to the compression mechanism, and this load is supported by a journal bearing. Generally, an axial length of the journal bearing is increased, thereby reducing a surface pressure, and reliability of the journal bearing is secured. Especially in the case of an eccentric bearing, there is tendency that a diameter thereof is smaller than that of a main bearing and a length of the eccentric bearing is relatively increased, thereby reducing a surface pressure of the eccentric bearing (see patent document 1 for example). Here, a diameter of a main bearing member is defined as Dm, a length thereof is defined as Lm, a diameter of an eccentric bearing member is defined as De and a length thereof is defined as Le. Then, a relation Lm/Dm<Le/De is established in patent document 1. This is because the diameter De of the eccentric bearing member becomes small and as a result, Le/De becomes great . That is, a ratio (=Le/De) of the length and the diameter of the eccentric bearing member is made greater than a ratio (=Lm/Dm) of the length and the diameter of the main bearing member. According to this, reliability of both the bearing members and shafts is ensured.
There is also such a configuration that the length Lm of the main bearing member is increased to establish a relation Lm/Dm>Le/De (see patent document 2 for example). The length of the main bearing member is increased, thereby increasing a contact distance between the shaft and the bearing member, and inclination of the shaft is suppressed. That is, reliability of both the bearing members and shafts are ensured like patent document 1.